US1786946A - Fuel-injection device for explosion engines - Google Patents

Description

Dec. so, 1930;

6 Sheets-5MM... 3

Arron/1era F. HoFMANN 1,786,946

FUEL INJECTION DEVICE FOR EXPLOSION ENGINES Y rfi-18d uay'ls. 1927 s sheets-sheet, 4

Hunllu, HHVNN un H nu HNIINIIIIHH H u H n H W m1 r I n` w n. l.. z n a Uhm E Dec. 3o, 1930. F. HOFMANN 1,786,946

FUEL INJECTION DEVICE FOR EXPLOSION ENGINES Filed May 13. 1927 6 Sheets-Shadi. 5

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`lastima Dec. 30, 1930. F. Hdl-'MANN FUEL -nmzc'rron'msvrcxs rdn sxrnoslou :Nexus rma nay 1s.` 1927 s shuts-smet, 6

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Patented Dec; 3Q,` 1930 A "UNITED STATES' PATENT OFFICE..

FRIEDRICH Hermann, or ,mULREr-oN-THE-RUHR, GERMANY, assIGNoR To RoLzwARrR Gas rURBINE Co., oEsAN FRANCISCO, CALIEORNIA, A CoRroRA'rioN o E DELAWARE FUEL- INJEC'rroupEvIcE ro'R ExPEsIoN ENGINES Application ula-d lay 13, 192'?, Serialo.

VVcan be obtained only' if the lcontents of the explosion chamber .are lcompressed before i nit-ion. From" said chamber thecombustion gases pass tothe turbine nozzle through an outlet controlled by a nozzle valve, said gases expanding on their way tothe turbine.v

It is customary to pass scavenging air througlh 20 the combustion chamber, the nozzle, and

turbine proper after'the `expansion ofthe v combustion gases, at a. pressure which lis but slightlyabove atmospheric or abovethe exhaust pressure of the turbine. As heretofore constructed, turbines-fofA this type, therefore,

A required air at` three different ressures: lowpressure air for scavenging, c arging air of l a moderate intermediate pressure, in order to obtain-combustion under the most favorable thermic conditions, and high-pressure air for atomizing, in-order to secure as thor- `ough an atomization of the oily (or other fuel) 'as ossible and thus to mix'such liquid fuel sufficiently with the charging air during the short period fof time available-for this pur-v pose. Accordingly, power plants of thisv type; as constructed hithertoV required three separate admission devices, viz.: a scaveng-' ing' air. valve, .a charging air valve, and ani; oil-atomizin-g valve.

My present invention effects a material simplification byconstructing the charging a1r` valve and the oil-supply nozzle in such a manner that the moderate or medium pressure of the charging airw'ill suiice for latomizing the li uid fuel. :I am thus enabledto .dis ense with'the high-pressure air. pum emp oyed heretofore for 'atomizing the fue as well 'as with the mechanism for operating such` air.

pump and with one ofthe valves associated 191,109, and in 'Germany April-1, 192'1.

withthe explosion chamber. I introduce the charging air' as an annular stream of cylindrical or conicalform, and inject the-oil or other li uid fuel in line jets into the interior of such ollow cone or cylinder while the air is in motion, so that the particles of liquid` fuel are entrained by the moving particles of ai-r in the interior of the conical or cylindrlcalfstream. The oil-supply nozzle of my improved injector is preferably arranged within the char ing air valve, through which the air is intro 4ucedto form an annular conical or cylindrical stream.

Several satisfactory examples of my lnvention are illustrated by the accompanying drawings, in which Fi 1 is a longitudinal section through a com ined air and jliquid fuel valve embodying my improvements; y

Figt 2is a diagrammatic view with parts in section, showing saidvalve an the actuating mechanism associated therewith; Fig. 3 is a partial longitudinal section through another form of my invention; Fig. 4 is ,an4 end view .of the valve'shown in Fig. 3; and Figs. 5, 6,

7, 7a and 8' are partial longitudinal sections of f our additional Vembodiments of my inven-v tion, Fig. 7a showingthe valve of Fig. 7 in association with its controlling mechanism.

In Figs. 1 and 2, .a indicates-a portion of the housing of an explosion turbine,'pr'0vided with an inlet b'through'which. the charging air from .any suitablev source is introduced under a moderate pressure, into a chamber' z which surrounds a valve -casing d and con municates. with an interior chamber y of said casing. The latter is formedwith a seat for the charging air valve f, opening toward the explosion lchamber indicated at c. This va ve, together with its tubular stem g, is

.movable lengthwise in the center-of the valve casing ,'inunison with. an `actuating 'piston Y Z, urged toward theclosed position ofthe valve by means'of a coiled spring-nn,- and ,toward` the open `position of the valve by means of a fluid (for instance oil) under pressure admitted through a channel n. A vent duct j is providedto allow air toenter or escape freely sothatthe're will be no material resistance to the movementof thev piston Z. v The longitudinal-channel h ofthe va'l've stemi" I said chamber.

g is closed at its outer end and provided with a lateral opening by which it communicates permanently with a channel o for the admission of liquid fuel. The tapering valve f has an interior chamber communicating permanently With the combustion chamber or explosion chamber c through tine duct-s in a plug or nozzle 7c, while'the communication of said chamber with the channel h is controlled by a check valve i opening toward Adjacent to the explosion chamber c, the valve casing Z is formed with a guide or nozzle c to direct the air issuing from the said casing, in such a manner as to mix it thoroughly with the fuel issuing from the nozzle Zt. To this end. the guide c may be given a conical form so as to cause the air stream to converge in front of the valu.- At

,the point of convergence, the air is at substantially its greatest velocity and is there struck by the fuel jet Whose velocity is comparatively low, so that the velocity differential between the air and fuel streams at such Joint is ver Oreat and thorough atomization y e e v of the fuel is promoted.

Vhen oil or other medium under pressure is admitted through the channel n (as by mechanism of the type described below with reference to Fig. 2) ,the piston Zwill he moved against the resistanceof the spring` m. bringing the valve f to the open position indicated by dotted lines in Fig. 1,'so that the charging' air from the inlet b and chambers z, y Will be discharged into the combustion chamber 0 in the form of a hollow conical jet. If While the'air valve is thus open, liquidfuel is delivered from the channel o through the channel ZL of the valve stem g, such fuel Will be projected in the form of fine jets through the tine ducts of the plug or nozzle 7c i'nto the hollow or annularvconical stream of air. The fuel will Ythus be atomized thoroughly and mixed intimately with the air; in fact, the fuel is not simply reduced to a spray of tine liquid globules, but converted into a vapor, so that an electric spark will ignite the mixture quickly and cause4 complete combustion.

In Fig. 2 I have indicated diagrammatically a suitable arrangement for actuating the valve described above. The channel n is connected by a pipe n with a port of a casing p in which a distributor q is mounted to ro tate.. The interior of'this distributor communicates with a.l supply of a medium` (oil) under pressure, for instance eight 'atmos-4 pheres, and has axdischarge port adaptedto communicate With the pipe n', once for each revolution of the distributor.' At4 other times, however, the pipe. n communicates, through the interior of the casing p, With an outlet port r, connected with a discharge pipe (not shown) in which atmospheric pressure prevails. Every time the interior of the dis.

ltributor g registers With the port leading to the pipe n', the fluid under pressure will reach ings. c these openings will together form an annular the piston Z and cause the valve f to open; as soon as the pipe n 1s again 1n communication -with the outlet port 1', the spring fm. will close port '1i from a fuel reservoir (not shown) and expels it through the outlet w and a pipe o into the channels o andh. I have indicated in Fig. 2 an automatic regulator of wellknoivn character, employing an overflow valve which is opened by a lever adjusted to different levels by the eccentric mechanism t shown at the right, the eccentric being controlled by the speed governor t operated by the shaft of the engine. The upstroke or Working stroke of the pump u will always begin at the same time, but the timing of the overflow va-lve'a,l Will vary according to the enginespeed, thus varying the amount of fuel delivered to the channels 0, h at each stroke of the pump u. I desire it to be understood that any other suitable control mechanism may be employed for the fuel pump, and,"ingeneral, any suitable'means for regulating the feed of fuel in accordance with the load on the engine may be used.

The construction illustrated by Figs. 3 and 4 has a guide e with a transverse Wall through Which the fuel nozzle k projects, said Wall having an annular series of converging open- The individual air jets issuing from air stream of'conical shape. Fig. 3 shows parallel longitudinal ducts 'in the fuel nozzle lc; they might, however, diverge in the-saine manner as in Fig. 1.

In Fig. 5, theopeningthrough which the air is discharged as an annular stream into the combustion chamber c, is formed 'be-A tween the inner cylindrical wall of an eXtension a of the housing a and theouter cylindrical Wall of an .extension f of the valve f. The stream of air issuing into the combustion chamber Will, in this case, have the shape of.

a hollow cylinder. The outlet ducts ofthe fuel nozzle k are preferably radial, as shown, in order that the fuel jets may impinge on the annular stream of air as soon as possible after its formation and thus be atomized most efficiently. l i

According to Fig. 6, the mechanism for actuating the valve f has been simplified by omitting the spring m of Fig. l and effecting the retraction of the valve by the pressure of the charging air itself. If the external atmospheric pressure is designated by pand if the hydraulic pressure behind the piston Z as well as the pressure in the explosion chamber be likewise equal to p just 'prior to chargin g said chamber, let further p designate the charging pressure, fthe eiective cross-section of the valve, f the cross-section of thevalve stem, a'nd F the cross-section of the piston, then the force pressing the valve against its seat'will be equal to (l2-p0) (F-) p0f y Since both p-po and, F- f are greater than zero, it follows that the product (2r-p0) (FL-f) likewise is greater than zero, and this product can readily be given a value greater than the other term, poi', so that there will be a positive force pressingthe valve' 'toward its seat. .When the valve is to be opened, this force would be overcome by increasing the hydraulic pressure. Reducing the hfydraulic pressure, would allow said posi, tive orce to becomepreponderant again and to close the valve. The force closing the valve would be greater than the pressure to be overcome during theopening of the valve, for the reason that during chargingthe counterpres` sure increases in the explosion chamber.

Fig. 7 illustrates a construction in which the' combined valve for the admission of the fuel'andof the charging air is disposed with inthe scavenging air valveof the explosion chamber, thus combining in a single element or unit all the devicesrequired for-charging and scavengingthe explosion chamber. The inner, valve casing d 'is surrounded b the sleeve valve y",l g` consisting ofa tu ular body anda ian e or bell constituting the valve proper. ai-d tubular body is surrounded by an annular piston-Z to which it is secured by a nut 15. The outlet end of the casing'd istapered, like the guide e of Fig. 1, and for a similar purpose. The stationary body a2 which has a seat forthe portion f.of

v sion cham er.

' the sleeve valve also forms a guide along which the piston lf moves. The body a2 and the valve casing d are bolted or otherwise secured to the housing a, provided atits outerA portion with a cylinder for the piston Z. B'etween the two parts a, d is formeda chaml ber 16'the port 'n2 of which is connected with a suitable hydraulic controlling device... The annular space between the body a2@ the sleeve -g communicates with an opening or nipple b connected with the pipe (not shown) valve f willbe forced open and scavenging'- air admitted to the explosion chamber. The hydraulic control of thls valve is independent 'of the hydraulic control ,of the charging air valve f, -which is effected by admitting oil or vother suitable 'medium under pressure, through the port or nip'ple fn.. `Devices like .the one shown at p, g in Fig. 2 may be employed to control the supply of oil under presment shown in Fig. 7 would'be associatedV with a fuel pump of any suitable character` (not shown), independent of the hydraulic sure to the ports a, n2 of Fig. 7. The arrangecontrol of the valves f and f,.and adapted to inject fuel at the proper time into the. chan- `nel I. and through the'nozzle c into the aunular streamv of charging air issuingirom the device when the valve f is open. The fuel conduit Vmay be provided with a check valve t Fig. 8 illustratesa kunitary structure combining a scavenging valve with a valve for the linjection ofthe charging air and of the fuel. The arrangement di'ers from the one shown in Fig'. 7 by the employment of springs for retracting the valves, instead of relying on air pressure to do this. The charging air valve f with its tubular stem g and actuating hydraulic piston EZ is again located within a housing a, which also receives the retracting lspring mand is connected through the port 01' nipple bwith the `reservoir from which the chargin air is supplied. At the end nearest the exp osion chamber, this housing has a portion provided with a cylindrical outer surface, surrounded .by a sleeve g. The latter has a seating surface for the charging air. valve f, and at its forward end forms the scavenging air valve f. The )sleeve g is surrounded 'by the tubular guide d located in the outer housing a and carries an annular` piston'l movable in a cylinder formed in said outer housing. An annular chamber-.

y formed between the pistdn Z and the flange.

by which the housing a is fitted to the hous- 111g a9', has a port n through which a hydraulic'mediurn under pressure may be admitted to operate the piston Z and open the scavenging airvalve f', in substantially the 'same manner as in Fig. 7. This valve may be seated either directly on a suitable surface of the outer housing a or a separate washer or seat member as may be provided, as shown;

Various modiications may be made withs defined inthe appended claims.

I claim: l

1. A device :for injecting air and fuel into a combustion chamber,- comprisin ra casing provided with a connection vfor t e admission of compressed air, with an outlet for the discharge ofeslielif compressed air, and with parting from the nature of my inven-v f a valve seat between said connection and said t outlet, a valve adapted to engage'vsaid seat and.` to establish or interrupt the passage of 'com ressed air to said outlet, a tubular stem movable in unison with said valve, the latter V being provided with a passage communicating with the interior of said stem for discharging fuel adjacent to said air outlet, a pump for supplying fuel to said stem, a piston connected with said valve and of greater area than such valve, one face of said piston being exposed to the pressure of said compressed air in such a way as to tend to seat said Valve, a cylinder in which said piston is movable, and a controlling device associated with said cylinder to admit an actuating medium under pressure into such cylinder on the side. of the piston opposite to the one exposed to the action of said compressed air, to move such piston into the valve-opening position. l

2. A device for injecting air and fuel into a combustion chamber, comprising a casing provided with aconnection for the admislsion of compressed air, with an outlet for the discharge of such compressed air, and with a valve seat between said connection and said outlet, a valve adapted to engage said seat and to establish or interrupt the passage of compressed air to said outlet, a tubular stem movable in unison with said valve, the latter being provided with a passage communicating with the interior of said stem for discharging fuel adjacent to said air outlet, a pump Afor supplying fuel to said stem, a scavenging air valve surrounding said casing and slidable thereon, and an outer valve casing provided with a seat for said scavenging air valve and with a connection for the supply of scavenging air.

3. A device for injecting air and fuel into a combustion chamber, comprising a casing provided with a connection for the admission outlet for the discharge of such compressed'air, and with a valve seat between said connection and said outlet, a valve adapted to engage said seat.

and to establish or interrupt the passage of lcompressed air to said outlet, a tubular stem movable in unison with said valve, the'latter being provided with a passage communieating with the interior ofy said stem for discharging fuel adjacent to said air outlet,a pump for supplying fuel to said stem, a scavenging air valve surrounding said casing and slidable thereon, an outer valve casing provided with a seat for said scavenging air valve, with a connection for the supply of scavenging air, and withl a cylindrical portion having a connection for the admission of an actuating medium under pressure, and an annular piston movable in said cylindrical portion and operativelyT connected with said scavenging air valve.

` 4. A device for injecting air and fuel into a combustion chamber ef a combustion engine comprising a casing pr vided with a connection for the admission of compressed air, with an outlet .shaped to discharge such compressed air in the form of an annular jet, and

with a valve seat between said connection and said outlet, a valve adapted to engage said seat and to establish or interrupt the passage of compressed air to said outlet, a valve stem movable in unison with said valve and provided with a longitudinal channel for the passage of fuel, a fuel pump connected to said channel and controlled from` the governor of the engine, a fuel nozzle carried by said valve and having an outlet arranged to discharge fuel into the stream of air admitted by said v'alve, and a check'valve in said channel for preventing return flow of the fuel.

5. A device for injecting scavenging air, chargii'ig air and fuel into a combustion chamber, comprising a fixed outer casing, a scavenging air valve movably mounted within said casing, a charging air valve movably mounted within said scavenging air valve, a fuel valve located within said air valve, conduits for conducting scavenging air, charging' air and fuel to the respective valves, and valve operating mechanism for opening said valves in predetermined timed relation.

A device for injecting scavenging air, charging air and fuel into a combustion chamber, comprising a fixed outer casing a hollow scavenging air valve movably mounted within and spaced from said casing and seating thereagainst, whereby an annular chamber is formed between4 said valve and said casing, a conduit for supplying scavenging air to said chamber, a charging air valve movably mounted within said first-mentioned valve and providedwith a stem, an annular compartmentbeingthereby formed between said scavenging and charging air valves, said stem being provided with a passage extending throughout the length thereof, the outlet of said annular compartment being controlled by said charging air valve, a conduit for feeding charging air to said compartment, a valve-controlled fuel nozzle in said charging air valve communicating with the passage in said stem and adaptedtov discharge a jet of fuel into the anular stream of charging. air flowing into the combustion chamber when said charging air valve is open, and valve operating mechanism for opening said valves in predetermined timed relation.

7 .'A valve for controlling the charge of air toja combustion chamber, comprising a casing provided ^with' a valve seat, a valve within saidl casing having a head adapted to engage said seat, a valve stem connected to said head, a piston mounted upon said stem in spaced relation to said head whereby an annu.- lar compartment is formed between said piston and said headbounded by said piston and head, said piston being slidable within said casing,'the area of the piston bounding said compartment being greater than the corresponding area of said valve head, a conduit for supplying compressed air to said compartment, and valve-opening mechanism for opening said valve, said valve,y after'the combustion chamber has been charged with air being closed, upon release of said valve-opening mechanism, by the pressure of the an' in said compartment against said piston.

8. A device for injecting air and fuel into the combustion chamber of a combustion enf gine, comprising a casing provided with a connection for the admission of compressed air, With an outlet, and With a valve 'seat at l said outlet, a valve adapted to engage said seat to establish or interrupt the passage of compresed -air to said outlet, the latter being shaped to discharge the compressed air in the form of an annular jet converging towarda point in front of said outlet, a valve stem movable in unison with said valve and provided with a longitudinal-channel for the pas' sage of fuel, means controlled from the governor of the engine for conducting. measured quantities of liquid fuel intermittently into saidehannel, and afuelnozzle carried by said valve and arranged to direct said fuel into the air jet in the vicinity ofsaid point of con-n c vergence, Where the Velocity of the air is substantially at a maximum, whereby an intimate mixture of said air and fuel is obtained.

FRIEDRICH HOFMANN.

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